Relations of the New-Zealand Fauna. 31 



Australia possesses two species of emu, one on the eastern and 

 the other on the western side, and one species of cassowary 

 on the northern, while five other species of cassowary inhabit 

 other detached islands, from New Britain and New Guinea to 

 the Molucca Islands. I believe that outside of New Zealand no 

 two species of struthious birds are found living in the same 

 district, while here we have now four species of kiwi, and not 

 long ago had at least half a dozen species of moa as well. 

 How can this be accounted for ? The solution is readily found 

 by examining the distribution of the cassowaries. Here we 

 have six species inhabiting six isolated localities. If now this 

 region of the earth were to be elevated, these six species might 

 mingle ; and if it were subsequently to sink again, all six 

 species would undoubtedly be driven to the higher lands, and 

 we should have in this supposed island a representation of 

 New Zealand inhabited by six species of Struthious birds. 



In order, therefore, to account for the numerous species of 

 Dinorms^ we must suppose an ancient continent inhabited by 

 one or two species to sink and the birds to take refuge on the 

 different mountain-ranges left as islands above the water. We 

 must suppose that they remained thus isolated from one another 

 for a sufficiently long period to allow of specific changes being 

 brought about, that then by an elevation of the land they 

 once more mingled together, and that, on subsidence again 

 taking place. New Zealand, as the central mountain-chain, 

 formed a harbour of refuge for them all. 



Whether this isolation of species points to some cause as 

 yet unrecognized, by which in the struggle for life no two 

 species of struthious bird can live in close proximity, I will 

 not venture to give an opinion ; but it is a fair subject for 

 inquiry, and one on which the careful study of the relative 

 ages of moa-bones might throw considerable light, and enable 

 us perhaps to understand the great mortality that must have 

 taken place amongst the moas when confined to these small 

 islands long before man set his foot here. 



The distribution, therefore, of the Struthious birds in the 

 southern hemisphere points to a large antarctic continent 

 stretching from Australia through New Zealand to South 

 America, and perhaps on to South Africa. This continent 

 must have sunk ; and Australia, New Zealand, South America, 

 and South Africa must have remained isolated from one ano- 

 ther long enough to allow of the great differences observable 

 between the birds of each country being brought about. Sub- 

 sequently New Zealand must have foi'mcd part of a smaller 

 continent, not connected either with Australia or South Ame- 

 rica, over which the moa roamed. This must have been fol- 



